Whenever there's a costume drama on screen, the props people have meticulously chased up old furniture, vintage cars, houses from the correct era and the right clothes (even the underwear – about which much that we know is gleaned from dolls' sets, since you don't leave your smalls to your descendants). But why do they so often get the hair wrong? In a recent Pride and Prejudice, they'd gone overboard with small rooms, animals passing the window, a very crowded Assembly room. Yet at least one of the girls had a straight straggle of hair down each cheek, even when receiving visitors! She'd have been sent back to her room by a real Mrs Bennet to do something about it.

Even in Atonement, the girl in a wartime hospital had two strands of hair hanging from the cap designed specifically to stop the nurses' hair dangling over the patients; and in the movie Julia, Vanessa Redgrave is shown as a 30s college girl with a mane of long curls, though such girls then favoured sleek little bobs.

And in the Julia McKenzie version of Marple, she is fine, but a blonde supposed to be young and glamorous has the deliberately dark parting favoured only in this century. Why? Doesn't anyone notice? Or can't even directors control their hairdressers?